Apparatus for thickening liquid slurry stocks



Feb. 2 3, 1954 s0 2,669,909

APPARATUS FOR THICKENING LIQUID SLURRY STOCKS Filed June 15, 1950 IN V EN TOR.

ALBERT G. GIBSON Patented Feb. 23, 1954 APPARATUS FOR THICKENING LIQUID SLURRY STOCKS Albert G. Gibson, Middletown, Ohio, assignor to The Black-Clawson Company, Hamilton, Ohio,

a corporation of Ohio Application June 15, 1950, Serial No. 168,270

8 Claims.

This invention relates to apparatus for thickening paper making stock and .other liquid slurry stocks.

The invention has particular relation to stock thickeners of the type which include a cylinder mold rotating in a vat of dilute stock and a couch roll or other device for removing the thickened pulp from the cylinder mold and discharging it to the discharge trough of the vat. The vat may also be provided with an overflow outlet to the discharge trough for direct discharge of dilute stock, so that the thickened product of the thickener is a mixture of the thick pulp from the cylinder mold and the more dilute stock discharged at the overflow. The present invention is directed particularly to the provision of simple and eiieotive means for varying and regulating the consistency of the thickened stock produced with this type of stock thickener by simultaneous adjustment of the consistency of the thickened pulp removed from the cylinder mold and the rate of discharge of the more dilute stock from the overflow to give the desired final consistency in the resulting mixture.

This desired result is obtained in accordance with the invention by mounting a driven transfer roll on the thickener adjacent the overflow and in spaced relation with the cylinder mold. This transfer roll is longitudinally fluted or otherwise formed with a plurality of angularly spaced compartments in its surface, and it is supported in close relation with the top of the overflow in such manner as to have running clearance therewith while substantially preventing flow of stock between itself and the overflow. Direct discharge from the vat to the discharge trough thus takes place over the transfer roll, and the rate of such discharge depends on the rate of rotation of the transfer roll, with the compartments in its surface acting to pick up stock within the vat and carry it above the overflow to the discharge trough.

In the operation of a stock thickener with this transfer roll, when the transfer roll is rotated in such direction that adjacent surfaces thereof and of the cylinder mold travel in the same direction, it acts to urge the pulp in the vat towards the surface portion of the cylinder mold which is rising above the level in the vat so that the pulp tends to cling to the cylinder mold instead of slipping back away from it, thus delivering more pulp at higher consistency to the cylinder mold than when the transfer roll is not present, and this has the further desirable result of materially increasing the capacity of the thick- All ener under given operating speeds. In addition, the transfer roll is provided with a variable speed drive for effecting ready adjustment of its speed of rotation to vary the rate of discharge of the more dilute stock from the overflow to the discharge outlet. Since this in turn determines the relative proportions of thickened pulp and more dilute stock delivered to the discharge trough, it provides ready adjustment to give the desired consistency in the resulting thickened mixture.

It is accordingly one of the principal objects of the invention to provide a simple variable control over the consistency of the thickened stock delivered from a stock thickener, and particularly to provide such a control which is adjustable to give a desired high consistency in the pulp received by the couch roll and desired relative proportions of this thick pulp and the more dilute stock discharged at the overflow of the vat.

Another object is to provide a stock thickener having a transfer roll mounted inposition to control the rate of discharge from the overflow of the thickener vat and equipped with a variable speed drive for effecting desired adjustment of the speed of rotation of the roll in accordance with the desired proportions of thick pulp and more dilute stock delivered to the discharge trough of the thickener.

Other objects and advantages of the invention will be apparent from the following description,

the accompanying drawings and the appended claims.

In the drawings- Fig. 1 is a somewhat diagrammatic side or end elevational view of a stock thickener embodying a transfer roll in accordance with the invention;

Fig. 2 is a top view of the thickener with the couch roll and doctor removed for simplicity of illustration; and a Fig. 3 is a fragmentary diagrammatic view illustrating the operation of the transfer roll.

Referring to the drawing, which illustrates a preferred embodiment of the invention, the thickener is shown as of the Decker type and includes a vat H] provided with an inlet flow trough II for the dilute stock and an overflow outlet lip 13 to the discharge trough [5 for the thickened stock. The white water outlet troughs It at either end of the vat are provided with adjustable overflow gates i1 having adjusting bars l8, and their lower ends are fitted at [9 for attachment to suitable conduit pipes. The cylinder mold 20 is mounted for rotation in the vat by means of bearings 2i and is driven by the motor 22 through a pinion 23 and'large gear 24. The cylinder mold is prosistency of the thickened stock delivered by a stock thickener including a vat adapted to be filled with dilute stock to be thickened and having a discharge trough and an overflow outlet for said dilute stock to said trough, a cylinder mold mounted for rotation within said vat and means for receiving and discharging the thickened stock from said cylinder mold to said trough, the improvement comprising the combination of a transfer roll mounted between said cylinder mold 1 separated compartments around said transfer roll,

means for rotating said transfer roll to cause said compartments to be successively filled with dilute stock within said vat and to carry said stock over said overflow outlet to said trough, and means for varying the speed of rotation of said transfer roll to regulate the rate of discharge of said stock from said overflow outlet.

2. In the apparatus for regulating the consis ency of the thickened stock delivered by a stock thickener including a vat adapted to be filled with dilute stock to be thickened and having a discharge trough and an overflow outlet for said dilute stock to said trough, a cylinder mold mounted for rotation within said vat and means for receiving and discharging the thickened stock from said cylinder mold to said trough, the improvement comprising the combination of. a transfer roll mounted for rotation above said overflow outlet in the path of flow of stock over said outlet and in spaced relation with said cylin der mold, means maintaining said transfer roll in running clearance with said overflow outlet substantially preventing flow of stock therebetween, generally straight vanes extending lengthwise of said transfer roll and substantially parab lel with the axis thereof to form a, pluralityof circumferentially separated compartmentsaround said transfer roll, means for causing said cylinder mold to rotate in such direction that the portion thereof adjacent said transfer roll moves upwardly, means for rotating said transfer roll the opposite direction from said cylinder mold to urge the stock in the space between said rolls towards said cylinder mold for increasing the volume of solid material picked up by said cylinder mold and also to cause said compartments to be suecessively filled with dilute stock within saidvat and to carry said stock over said overflow outlet to said trough, and means for varying the speed I for receiving and discharging the thickened stock from said cylinder mold to said trough, the provement comprising the combination of a trans-- fer roll having generally straight vanes extending lengthwise and substantially parallel with-the axis thereof to form a plurality of circumferentially separated compartments around said transfer roll, means supporting said transfer roll for rotation about an axis located above the level of said overflow outlet and in the path of flow of stock over said overflow outlet, a curved lip on said outlet arranged in substantially concentric relation with the axis of said transfer roll and in running clearance with the surface of said transfer roll, said lip being of substantially the same angular extent as the mouth of each said compartment for substantially preventing flow of stock between said transfer roll and said lip, means for rotating said transfer roll to cause said compartments to be successively filled with stock within said vat and to carry said stock over said lip for discharge into said trough, and means for varying the speed of rotation of said transfer roll to regulate the rate of discharge of said stock over said lip.

4. In the apparatus for regulating the consistency of the thickened stock delivered by a stock thickener including a vat adapted to be filled with dilute stock to be thickened and having a discharge trough and an overflow outlet for said dilute stock to said trough, a cylinder mold mounted for rotation within said vat and means for receiving and discharging the thickened stock from said cylinder mold to said trough, the im provement comprising the combination of a transfer roll mounted for rotation about an axis between said cylinder mold and said outlet in the path of flow of stock over said outlet and in spaced relation with the surface of said cylinder mold, a plurality of generally straight vanes arranged generally longitudinally on and substantially parallel with the axis of said transfer roll and in angularly spaced relation around said roll to form a plurality of circumferentially separated compartments around said roll, a curved lip on said overflow outlet arranged in substantially concentric relation with the axis of said transfer roll and in running clearance with the outer edges of said vanes, said lip being of sufliciently greater angular extent than the angular spacing between the outer edges of adjacent said vanes to effect substantial sealing against flow of stock between said projections and said lip, means for rotating :said transfer roll to cause said compartments to be successively filled with dilute stock within said vat and to carry said stock over said overflow outlet to said trough, and means for varying the speed of rotation of said transfer roll to regulate the rate of discharge of said stock from said over- 7 flow outlet.

5. In the apparatus for regulating the consistency of the thickened stock'delivered by a stock thickener including a vat adapted to be filled with dilute stock'to be thickened and'having a discharge trough and an overflow outlet for said dilute stock to said trough, a cylinder mold mounted for rotation within said vat'and a couch roll supported in driven contact with said cylinder mold to form a nip therewith adjacent and above the level of said overflow outletand adapted to receive thickened stock from said cylinder mold for discharge to said discharge trough, the improvement comprising the combination of a. transfer roll mounted between said nip and said overflow outlet in spaced relation with the surfaces of said cylinder mold and said couch roll and in the path of flow of stock over said overflow outlet, means maintaining said transfer roll in running clearance with said overflow outlet substantially preventing flow of stock'between the surfaces thereof, generally straight vanes extending lengthwise of said transfer roll and substan- -tiallysi parallel i'withsetheaaxisathereof Btu. for-mt a pluralityiofa circumferentially;separated compartmerits :aroundsaidatransfer roll-,- means forerotating s aide transferroll tecausesaidtcompartments *iftOfbE successively :fil-led w-ith stocls within .said'vat mandztoecarryisaid? stock over saidoverfiow outlet forydischargeinto:said trough; andam-eans:.=f;or "cwaryinguthe speedf rotation ofr saidatransfer roll w'rto dzegulate the rate of: discharge to? saidastock ix 'from'saidoverflow--outlet. (Si-In the :apparatus sfori-regulatingwhe consistgiiency of the thickened-stockdeliveredqby a stock thickenerincludingl a vatadaptedte-befilled-with stock's-to be%thickenedand-having a: discharge trough andan "overflow outlet toa-saidatrough; a cylinder mold mountedwfor-rotation-"within .said K v vat and an couch I011: supported :in: drivenrcontact with said icylinderrmold itoaform o a. ip; therewith adjacent and above the level of said outlet; and sadapted to receive :thickened :stockirom said. 0371 '-":i-mier mold foridischarge 2to= said .trough-,.theim- -z-provementcomprising. the combinationofv atrans- :fer roll' mounted betweerr saidvnipz anclesaidevert .flOWi outlet 1 in Spaced-re1atiDn-;With=:the surfaces or said cylinder mold-andsaid couch 1101b and -in wthe'pathof flow of stock'oversaidoverfiowaoutlet, :at generally straight vanesextendinglengthwise 0f -.zsaid-: transfer vrolland substantiallyvparallelwith -.=..the'.1-axis ithereof :toxform aplurality, of; :circum- :'=-f'erentially separated? compartments! around said w-ctransferrolli means maintaining tsaid'transfer roll with said vvanes in running clearance with said r'cverflow outlet I substantially preventing: I flow: of wstock between the surfaces thereofrmeans ford-ro- Jafitating-esaida transfer rolliin' the .direction rtor cause ithe stock .imsaid rvat to flowsintotthe space be- 'itween: said-rollsrandv-said cylinder mold/for dinwcreasinguthe consistency: of the;.thiekened stook wreceived-by' said couch 'IOllg'afl-Ild means for rvar-y- =-:ing':the-jspeed-of rotation: of zsaid ztransier'rolhto vwegulate 'therrate ofodischargesof -stecla overesaid tra nsferroll toosaiddischarge trough.

7. In; the apparatus f or regulatingithe consist- 1' alloy of: the thickened-1 stock del-iveredqbys a-stock thickener; including a 'vat adaptedtobafilledwith 1? stock" tor-be thickenedand having i an discharge :trough and-an: overflow-outlet :to=-saidw-trough; a cylinder mold mounted zfor-v rotatiomwithini said vataand a icouchrollsupportedfinrdrivencontact swithe'saidwcylinder-:mold rte-form a: nip therewith o '-':adjacent--and above;the1level-ofzsaid outlet-hand .v-adapted to receive thickenedistoeke-fromasaidycylfinder mold :for discharge-to I said trough,-2--the; im-

provement comprising the combination't'of-a trans- .v-eier roll mounted for -'rotationsaloove sai'd overflow I for rotath gssaiditransferrollz-in-i-thez sameedirec- '.;tion assaidtcouch rollttotcause said-vanes thereon K tourge the stochwithin said vat towards said-mix -for. increasing the consisten;cy,, ofthe :thickened 5 stQckIecei-Ved. bysaid-couch ,roll and alsortozcause said, compartments ,to' carry stock from within said vat across said overflow outlet .to. said-,discharge-trough, andmeans for varying the-speed J'ofrotation'of said transfer roll in. accordance with .the desired relative proportions of the vthickened .stockdischarged to said .troughrfrom said couch .roll .and themore. dilute stockdischargd tovv said .trough over said-.tran'sferroll. V

8L In the apparatus .for regulating :the'con'sistency .bf. the thickened stock'ldelivered -by.. at stdck .ithickenerincluding a vat adapted to be filled with stock, to. be. thickened. and having. av discharge trough andv an overflowoutlet to said trough; a ei'rlindenmold .mounted' for. rotation .withinisaid .vat: and a couch rollnsupported' in "driven contact i'with'said cylinderomold to'iiorm a nip therewith 'Iadjace'nt'and above thelevel of said cutleti'a'nd adapted to receive thickened stock from sawmi- ".xinderlm'old for dischargeito said trough; theiimg- 'pr'ov'ement'comprisingthe combination of "a transfife'r roll havinggenerallystraight vanes extending "lengthwise "and substantiallyj parallel. with'the axis thereof to form a plurality 'of circumferentially separated compartments aroundth'esurface thereof, means "supporting said tr'ansfer"roll:for rotation about anaxisbetween' said inipa'nd'ts'aid overflow outlet in spaced relation with"the"sur- ,faces of said cylinder mold "and"said*couchfiroll "and i'n'thetp'ath of flow'of stock oversaid overflow outlet, a curved lip'onsaidovrflowxbutletarranged in substantially' concentricrelation with *the axis of'zsaid transfer r'oll' and'ihrrunning'"clearfiance with said'vanesLon said transfer 'ro11;"-"said "lip being of substantially the same angular extentasthe mouth of each saidv compartment for 'substantially'p preventing t'flow "of 'sto'ck' "between i-" 's'aid' transfer roll andtsaidlip, means forrota'ting said transfer roll 'to' cause *s'aidcompartm'ents to ".Jbe successively filled with stock; within said-vat ii'andtoocarry said stock over said'lipfor discharge jintos'aid trough; and meansforwaryingthe' speed *stof"rotation"iof"" said "transfer rollto' regulatethe 'r'ate'o fldis'charge "of 'said stock over'sai'd lip.

" ALBERT G. J GIBSON. 

